Fool Proof Price Validation Custom Function

[Ryan H]

I'd like to test and see if anyone knows a better way to write this function.
The goal of the function is to test if the textboxes on a userform have a
valid price in them. Some prices I will or will not allow a negative price,
some prices can or can not be zero, and most of all the prices need to be
numeric. Does any one have a better way of doing this? I want this fool
proof!

Sub DataValidation()

' ensure valid price adder
If ValidPrice(tbxAdderPrice, True, True) = False Then Exit Sub

' ensure valid unit price
If ValidPrice(tbxUnitPrice, False, False) = False Then Exit Sub

' ensure valid crate price
If ValidPrice(tbxCratePrice, False, True) = False Then Exit Sub

End Sub


Function ValidPrice(objControl As Object, bolAllowNegative As Boolean,
bolAllowZeros As Boolean) As Boolean
' is called to ensure proper format of a price entered in a textbox.
' can be used for negative/postive prices

SubName = "ValidPrice"

' set default to True
ValidPrice = True

' test if zero, if zeros are not allowed
If Not bolAllowZeros Then
If Val(objControl) = 0 Then GoTo InvalidPrice
End If

' test if numeric
If IsNumeric(objControl) Then

' test if negative, if negatives are not allowed
If Not bolAllowNegative Then
If Len(objControl) <> Len(Replace(objControl, "-", "")) Then
GoTo InvalidPrice
End If
Else
If Not bolAllowZeros Then
' if not numeric
GoTo InvalidPrice
End If
End If

' format control
objControl = Format(objControl, "#,##0.00")

Exit Function

InvalidPrice:

ValidPrice = False
StopCode = True

strPrompt = "Problem"
intButtons = vbCritical
strTitle = "Please enter a valid price for " & objControl.Tag & "."
MsgBox strTitle, intButtons, strPrompt

End Function